armv8_dpm: retrieve only necessary registers on halt

to speed up debugging, don't load the complete register context
on a halt event, load only those registers that might be
clobbered during debugging.

Change-Id: I0b58e97aad6f28aefce4a52e870af61e1ef1a44f
Signed-off-by: Matthias Welwarsky <matthias.welwarsky@sysgo.com>
Reviewed-on: http://openocd.zylin.com/3995
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

diff --git a/src/target/armv8_dpm.c b/src/target/armv8_dpm.c
index ac53460ebfbee017426438f1f314a30f2bdbaa39..e5d10df6e791d6a6e16119bba3d446d230e15e1c 100644 (file)
--- a/src/target/armv8_dpm.c
+++ b/src/target/armv8_dpm.c
@@ -718,14 +718,22 @@ int armv8_dpm_read_current_registers(struct arm_dpm *dpm)
        cache = arm->core_cache;
 
        /* read R0 first (it's used for scratch), then CPSR */
-       r = cache->reg_list + 0;
+       r = cache->reg_list + ARMV8_R0;
        if (!r->valid) {
-               retval = dpmv8_read_reg(dpm, r, 0);
+               retval = dpmv8_read_reg(dpm, r, ARMV8_R0);
                if (retval != ERROR_OK)
                        goto fail;
        }
        r->dirty = true;
 
+       /* read R1, too, it will be clobbered during memory access */
+       r = cache->reg_list + ARMV8_R1;
+       if (!r->valid) {
+               retval = dpmv8_read_reg(dpm, r, ARMV8_R1);
+               if (retval != ERROR_OK)
+                       goto fail;
+       }
+
        /* read cpsr to r0 and get it back */
        retval = dpm->instr_read_data_r0(dpm,
                        armv8_opcode(armv8, READ_REG_DSPSR), &cpsr);
@@ -735,7 +743,7 @@ int armv8_dpm_read_current_registers(struct arm_dpm *dpm)
        /* update core mode and state */
        armv8_set_cpsr(arm, cpsr);
 
-       for (unsigned int i = 1; i < cache->num_regs ; i++) {
+       for (unsigned int i = ARMV8_PC; i < cache->num_regs ; i++) {
                struct arm_reg *arm_reg;
 
                r = armv8_reg_current(arm, i);